蓝桉、直干桉主要材性和生长性状的 遗传参数和遗传增益测算

由云南省澄江县14年生桉树实生种子园保留的育种群体4个区组内，从蓝桉和直干桉中各抽30个家系对它们的纤维长度、木材密度、树高和胸径4个性状的遗传力、遗传相关和遗传增益作了估算。蓝桉纤维长度和木材密度的单株遗传力分别为0.6745±0.0746和0.3546±0.1010；直干桉两性状的遗传力分别为0.3416±0.1011和0.0670±0.0850。两树种的纤维长度与其余3性状的遗传相关系数均为正值，而木材密度与树高和胸径的遗传相关系数均是负数。提出以纤维长度和树高作为蓝桉、直干桉的主要选择性状，并提出了选择方法和标准。蓝桉的选择指数方程为I1=Fr+9.9146H；直干桉的为I2=Fr+0.9809H。为下一步高世代育种应注意的事项作了建议。     

The use of near-infrared scanning for the prediction of pulp yield and chemical properties of Pinus patula in the Mpumalanga escarpment area of South Africa

Near-infrared (NIR) scanning technology is regarded as a potential tool for rapid determination of wood properties, which can substitute time-consuming and costly traditional methods. Pinus patula is the most important softwood species in South Africa, and this study is aimed at developing NIR calibration models for quick prediction of its pulp yield and chemical composition. A total of 85 trees from 17 plots, covering the range of site conditions in the Mpumalanga escarpment area, were sampled. Two samples were taken from each tree: a 1 m billet above breast height and a 20 mm disc at breast height. The billet was pulped using the kraft pulping process to determine pulp yield. The disc was ground into sawdust and the chemical composition was determined using conventional wet chemistry. Sawdust was scanned on a NIR spectrophotometer to produce NIR spectra. Calibration models to predict pulp yield, cellulose and lignin content were developed by applying chemometrics and partial least squares regression. Validation and determination of prediction accuracy of the models were performed using independent data. The prediction of cellulose and lignin were acceptable with correlations of determinations (r ²) of 0.71 and 0.70 respectively. Standard errors of prediction were generally low (less that 0.86) for all the models. The prediction r ² for both total and screened pulp yield were only 0.62. Although the cellulose and lignin models can be used with confidence, the expansion of the sample size for follow-up research must be considered in order to increase the variability of tested wood properties and improve the prediction strength of the models. The NIR calibration provided in this study can contribute to the efficient examination of forest site-to-wood quality relationships that would enhance precision forest management and wood processing efficiency.     

Calibration and Uncertainty Analysis of a Carbon Accounting Model to Stem Wood Density and Partitioning of Biomass for Eucalyptus globulus and Pinus Radiata

There is a need to calibrate models for carbon accounting in forest systems if they are to be applied for carbon trading and off-set schemes. One such model, Full Carbon Accounting Model (FullCAM), calculates stem mass by taking annual inputs of tree growth in stem volume and multiplying these by basic stem wood density. Stem mass is then multiplied by user-entered coefficients to determine the mass of other tree components. Using datasets of Pinus radiata and Eucalyptus globulus that comprised of between 73 and 187 observations, we determined empirical relationships that can be used in FullCAM to relate basic stem wood density to stand age, and masses of bark, foliage or branches to mass of stem wood for these two species. All fitted relationships were highly significant (p < 0.001), explaining between 35 and 89% of the variance. These calibrations were then tested using three case studies where data on volume yield curves and repeated measures of biomass of stand components were available: one of P. radiata and two of E. globulus. Although accumulation of biomass in foliage and branches were not well predicted by the model, sensitivity analysis showed that this was relatively unimportant to total carbon storage because of the dominance of the stem, particularly once the stand is older than 5 years. Indeed, FullCAM accounted for 99% of the variance in measured above-ground biomass at all three sites because calibrations for the mass of stem was reasonably well constrained. Uncertainty analysis showed that despite the standard errors of parameters used in relationships for basic density and biomass partitioning, and for estimates of carbon contents of tree components, we can be 95% confident that sequestration of carbon in trees and debris of Pinus radiata and Eucalyptus globulus plantations are, on average, within 13% of that predicted by FullCAM. Ensis is a joint venture between CSIRO FFP P/L and Scion Australasia P/L     

Application of the stock change and the production approach to Harvested Wood Products in the EU-15 countries: a comparative analysis

With the analytical tool: Frankfurt Harvested Wood Products (HWP) Model, carbon stocks and carbon stock changes of HWP, either in USE or in LANDFILLS, have been evaluated from the readily available statistical data base of the FAO, FAOSTAT, on the wood commodities: “Sawnwood and Wood-based Panels” and the paper commodities: “Paper and Paperboard”. Essential differences have been found between the individual 15 EU countries in the comparison of the Stock Change Approach and the Production Approach, as well as in the comparison of the stock changes of HWP with the National Greenhouse Gas (GHG) budgets. The stock changes for the HWP in USE within the EU-15 Community have been calculated to be 10.83 Mt C/a (39.71 Mt CO₂/a) based on the Stock Change Approach and 9.81 Mt C/a (35.97 Mt CO₂/a) for the Production Approach, respectively. These numbers can be compared to the total GHG Inventory of the EU-15 of 4,095 Mt CO₂ equivalents, including all six Kyoto gases, which shows that the carbon sequestration of HWP in USE is of the order of 1% relative to GHG Inventory. The GHG balance for the carbon stock changes of HWP in LANDFILLS is of similar magnitude as for the HWP in USE, and therefore a sink when methane outgasing is disregarded. However, when methane outgasing is considered, which is formed as a 1:1 mixture with CO₂ under the prevailing anaerobic conditions the GHG balance results in minus 10.0 Mt C equivalent/a and minus 10.6 Mt C equivalent/a for the Stock Change Approach and the Production Approach under the parameters chosen in this study. Presented in Dublin, October 6–9, 2004, COST-21 Plenary Session.